The erect abdominal x-ray shows the ‘String of Beads’ sign, which is caused by a line of gas bubbles trapped between the valvulae conniventes. This sign is seen when the dilated small bowel is filled with fluid and is diagnostic of small bowel obstruction.

The supine abdominal film shows the ‘Stack of Coins’ sign; this is caused by the close alignment of the valvulae conniventes across the dilated small bowel wall.

The above patient had adhesive small bowel obstruction.

Reference: Grainger & Allison’s Diagnostic Radiology, a Textbook of Medical Imaging.